2643655680 has 264 divisors, whose sum is σ = 9265737312. Its totient is φ = 696877056.

The previous prime is 2643655667. The next prime is 2643655681. The reversal of 2643655680 is 865563462.

2643655680 is a `hidden beast` number, since 2 + 64 + 36 + 556 + 8 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2643655681) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4745962 + ... + 4746518.

Almost surely, 2^2643655680 is an apocalyptic number.

2643655680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2643655680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4632868656).

2643655680 is an abundant number, since it is smaller than the sum of its proper divisors (6622081632).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2643655680 is a wasteful number, since it uses less digits than its factorization.

2643655680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 691 (or 670 counting only the distinct ones).

The product of its (nonzero) digits is 1036800, while the sum is 45.

The square root of 2643655680 is about 51416.4922957605. The cubic root of 2643655680 is about 1382.7222885399.

The spelling of 2643655680 in words is "two billion, six hundred forty-three million, six hundred fifty-five thousand, six hundred eighty".